1. Field of the Invention
The present invention generally relates to airplane cargo loaders, and more particularly, to protect airplane cargo from the environment, while cargo is being loaded and unloaded.
2. Background Description
Air cargo accounts for a major portion of air traffic today. Air cargo carriers such as AFA, DLH, CLX, SIT, CAT, KAL, CHI, UAE, for example, each operate a fleet of aircraft, primarily transporting cargo nationally and internationally for next day delivery. These carriers have been successful in transporting cargo over long distances at a cheaper price and faster than for cargo shipped with ground transportation. Since these carriers ship cargo all over the world, some cargo is likely to encounter temperature extremes, e.g., originating in extremely cold environments, such as Alaska, destined for much hotter locations like Dubai or vice versa.
Typically, the cargo is stored on the ground in some sort of a warehouse at its origination or destination point. Large items may be stored in bulk storage. Smaller items may be secured in cargo containers. Where applicable, cargo may be stacked onto pallets, 96 in. (244 cm) wide by 125-238.5 in. (318-606 cm) long. At the aircraft the cargo is loaded onto a cargo loader. The cargo loader raises and lowers the cargo and acts as a conveyer for transferring the cargo to/from the aircraft. If the aircraft is berthed on the tarmac, motorized vehicles pull a trailer or multiple chained trailers (known as cargo trains) that are loaded with cargo in bulk, pallets and/or cargo containers. The cargo trains ferry the cargo between ground storage and an aircraft.
Typically, cargo loaders are elevatable platforms that may be fixed on a motorized mobile base for positioning the loader at an aircraft in a berth on the tarmac or fixed at a jetway. An operator can either raise the platform to the cargo door of an aircraft or lower the platform to ground level or slightly there above for loading at a storage bay door or from a cargo train. With the platform elevated, cargo can be transferred to/from an aircraft cargo hold; with the platform lowered, cargo can be transferred to/from ground storage.
Frequently, a cargo load includes relatively delicate cargo that may be prone to destruction if exposed to the wrong environmental conditions, e.g., exposing tropical flowers or bananas to frigid air or chilled/frozen food or fish to tropical temperatures. Consequently, ground storage, cargo trains and aircraft cargo holds all have controlled environments, i.e., they are heated and air conditioned. Unfortunately, while the storage may be environmentally controlled, loading and unloading currently requires holding cargo bay doors open at loaders, at least until a cargo train is unloaded/loaded or the cargo bay is full/empty. Since a typical cargo bay door must be large enough for cargo container or fully loaded 10 foot (305 cm) tall pallets to pass through, holding one or more cargo bay door(s) open makes it difficult to maintain the cargo bay at its desired temperature and humidity. Consequently, this may unintentionally expose the cargo to external environmental conditions that, depending upon location and time of year, may be extreme (e.g., temperature, wind, and rain) and hazardous to the cargo.
Thus, there is a need for protecting air cargo from environmental extremes during loading and unloading and more particularly for maintaining aircraft cargo holds at their intended environmental conditions during transfers to protect the air cargo being transferred from external environmental extremes.